12. If sin 123" = a, find sin 246 A) 1 - 2a2 B) 2a C) 2a2 - 1 D) 1 + 2a2 E) 1 - 2a 13. Calculate the total surface area of a rectangular parallelepiped measuring 6mm, 7mm, 12mm. A) 386mm B) 680mm C) 768mm D) 640mm E) 396mm 14. How many grams of water need to be evaporated from 250 g of 20% sugar solution to get 25% solution? 15. How many degrees does the second hand of a clock move in 20 seconds? 16. find the number of the roots of the equation cos 2x = 1 + sin x in the range [- 7: =]- 17. Find the value of the following expression 5logs 3+7logs 3+=logs 3+-. A) log3 5 B) 3 C) 9 D) 4,5 E) 1,5 18. Find the area of rhombus 19. Find [a - b| if ab = 6 and z . 2 = 37 for the complex number z = a + bi 20. Find the value of the following expressions 19+ 4v5. V5-2 21. 30 students enrolled in math and physics clubs, including 6 in both clubs. If the number of students enrolled in a math club is twice the number of students enrolled in a physics club, how many students are enrolled in a physics club? 22. Factor the polynomial 49a2 - b2 + 14a + 1